Deciphering platinum dissolution in neural stimulation electrodes: Electrochemistry or biology?

Area of Science:

• Biomaterials Science
• Neuroscience
• Electrochemistry

Background:

• Platinum (Pt) is crucial for neural prosthetics like cochlear implants and deep brain stimulators.
• Pt dissolution during electrical stimulation is known, causing corrosion and particle release.
• The impact of Pt dissolution products on neural tissue health and device function remains poorly understood.

Purpose of the Study:

• To critically analyze Pt dissolution mechanisms in neural stimulation by reviewing fuel cell research.
• To identify electrical, chemical, and biological factors influencing Pt dissolution.
• To discuss host responses to Pt degradation products and explore mitigation strategies.

Main Methods:

• Literature review focusing on Pt dissolution mechanisms in fuel cells and neural stimulation.
• Analysis of in vitro and in vivo studies on Pt dissolution.
• Evaluation of electrical, chemical, and biological factors affecting Pt degradation.
• Review of strategies to mitigate Pt dissolution.

Main Results:

• Stimulation parameters (charge, potential) and chemical factors (electrolyte, pH) influence Pt dissolution.
• Proteins can mitigate Pt dissolution, while cellular responses like fibrosis may impact it.
• The relationship between electrode electrical properties and Pt dissolution is debated.
• Cytotoxicity of electrically stimulated Pt is similar to known Pt compounds, but clinical levels are lower.

Conclusions:

• Understanding Pt dissolution mechanisms is complex due to multiple interacting factors.
• Further research is needed to assess long-term Pt production and tissue impact.
• Mitigation strategies like optimized stimulation and material coatings are essential for safe neural device operation.